Lock-out for party-lines or extension-telephones.



C. L. GOODRUM.

LOCK-OUT FOR PARTY-LINES 0R EXTENSION TELEPHONES.

APPLICATION FILED DEC-5| I914.

Patented May 30,191

M veh for. Chair/es L. Good/Wm.

CHARLES E. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COMPANY. INCORPORATED, A CORPORATION OF NEW YORK.

LOCK-OUT FOR PARTY-LINES OR EXTENSION-TELEPHONES.

Specificatiers Patent. Patented May 3@, Illgflfi.

Application filed December 5, 1914. Serial No. 875,578.

To all whom it mag/concern:

Be it known that 1, CHARLES L. GOODRUM, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Lock-Outs for Party-Lines or Extension-Telephones,

of which the following is a full, clear, con-,

a 011 the same line.

branch lines connected to the same telephone line, whereby a branch in use is locked in on the common two-w1re line and all the other parties on the line are cut out.

The invention may be more readily understood by reference to the accompanying drawing which shows the preferred embodiment of the invention.

The invention is illustrated in the accompanying drawings in which Figure 1 illustrates the invention as ap plied to the subscribers of a four-party line and connected to a manual ofiice. Fig. 2 illustrates the central office connections for an automatic system, which may be substituted for the manual connections of Fig. 1.

Referring to the drawings, Fig. 1, A, B, C and D represent the subscribers stations of a four-party line, the several subscribers branches being connected to the same twowire telephone line 1, 2. The telephone line extends through the two windings of the slow-acting cut-out relay 3 and the normally closed contacts 4, 5 of the slow-acting cut-in relay 6 of the first station to the next station, and so forth through the first three stations. Each of the stations A, B and C is thus provided with a cut-out relay 3 and a cut-in relay 6 having similarly arranged contacts. It is unnecessary, however, to provide the fourth station D with such relays. The telephone line is normally extended to each subscribers telephone set through the windings of the corresponding cut-out relay 3 and the normally closed contacts 7, 8 thereof and the windings of the cut-in relay 6. The operation of the relay 6, which operates more quickly than the relay .3, closes the contacts 9 and 10 and thereby closes paths in parallel with the paths in which contacts 7 and 8 are included, so that when the relay 3 is operated the circuit of the subscribers set is not broken even though its normal connections through contacts 7 and 8 are open. Since the operation of the relay 6 opens its contacts 4 and 5, the succeeding stations in the train are thereby cut out. Any station nearer the central oifice is cut out by the operation of that stations cut-out relay 3.

As hereinbefore stated, the invention is applicable to either a manual or an auto matic telephone system. The telephone line is, therefore, shown as terminating at the central office in a jack 12, and cooperating therewith is shown a plug 13. At the central oflice there is also provided the usual line relay 14, cutoff relay 15 and line lamp 16. The central oflice connections for anautomatic system, are indicated in Fig. 2, the line finder being indicated at 17, and the line relay 14 being provided with a contact spring 18 which controls the closure of the circuit of the starter wire 19.

The operation of the particular embodiment of the invention shown in the drawing is as follows: Let it be assumed that one of the subscribers, for example, the subscriber at station B, wishes to institute a call. He removes his receiver from its book, thereby closing a circuit as follows: from battery X at the central office, through contact 20 of cutofi relay 15, wire 2, winding of relay 3' and contact 5 of station A, to station B, and, at that station, through windingv of relay 3, contact 8, winding of relay 6, wire 21, subscribers set, wire 22, winding of relay 6, contact 7, winding of relay 3, back to station A, and, at that station, through contact 4, winding of relay 3, wire 1, contact 23 of relay 15, and winding of relay 14 to battery. The relay 3 at station A and the relays 3 and 6 at station B being in this closed circuit, said relays are operated. Since the relay 6 responds more quickly than relay 3, the connection to the line of the branch 21, 22 of station B is maintained through contacts 9 and 10, although its normal connections through contacts 7 and 8 are broken. The operation of relay 6 at station B opens its contacts 4 and-5, thereby cutting out stations and D. The operation of relay 3 at station A opens its contacts 7 and 8, thereby cutting out station A. Station B, the calling station, is thus locked in on the line and the other stations cut out.

If it be assumed that the subscriber at station D is the first to institute a call, the

' circuit closed when he removes his receiver from the hook includes all of the relays 3 and none of the relays 6.. Station D thus remains connected to the line through its normal connections at contacts 4 and 5 of station 0, whereas the other stations are cut out by the operation of their respective cutout relays 3-. V V

' The cut-out relays 3 and the cut-in relays 6 are shown as inserted in the transmission circuit, but since said relays are of the slowrelease type and may employ a short-circuited secondary winding in the form of a copper tube, the transmission loss is not very great. The broader aspects of the lnvention d1sclosedherein form the subject-matter of a 'copending application Serial No. 875,577 of closed contacts of-said cut-out relays.

2. In a telephone system, the combination of a telephone line; a plurality of branch lines connected thereto; a series'of cut-out relays included in the telephone line and individual to the branch lines; cut-in relays included in the branch lines and individual thereto; said telephone line between said branch lines including normally closed contacts of said cut-in relays, said cut-out relays having normally closed contacts included in the normal connections of the branch lines to the telephone line, and said cut-in relays having locking circuits in shunt of said normally closed contacts of said cut-out relays.

3. In a telephone system, the combination of a two-wire telephone line; a plurality of branch lines connected thereto; a series of cut-out relays each having two windings included in the respective wires of the telephone line; cut-in relays individual to the branch lines and each having two windings ,included in the respective wires of its branch line; said cut-out relays having normally closed contacts included in the normal connections of the branch lines to the telephone line, and said cut-in relays having locking circuits in shunt of said normally closed contacts of said cut-out relays.

4:. In a telephone system, the combination of a two-wire telephone line; a plurality of branch lines connected thereto; a series of cut-out relays each having two windings included in the respective wires of the telephone line; cut-in relays individual to the branch lines and each having two windings included in the respective wires of its branch line; said telephone line between said branch lines including normally closed contacts of said cut-in relays, said cut-out relays having normally closed contacts included in the normal connections of the branch lines to the telephone line, and said cut-in relays having locking circuits in shunt of said normally closed contacts of said cut-out relays.

In witness whereof, I hereunto subscribe my name this 3rd day of December A. D.,

CHARLES L. GOODRUM.

Witnesses:

E. EDLER, K. L. STAHL.

7 Copies of this pstent'nlay be obtained for five cents each, by addressing the "Commissioner of .Pstents.

' Washington, D. G." 

